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EP0206203A2
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Recording and reproducing apparatus using a modulator/demodulator for Offset Quadrature Differential Phase-Shift Keying
Assignee: Hitachi Ltd
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Filing: 1986-06-16
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Granted: —
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Expires: 2006-06-16
Abstract
Abstract In an offset quadrature differential PSK modulator, input digital data is first converted by a serial-parallel converter into a first signal Xk and a second signal Yk (in which k is an integer) corresponding to even and odd bits of the digital data respectively with code change points thereof having a mutual deviation of one half data period and, after conversion by differential coders into data Pk = Xk ⊕ Pk-1 and Qk = Yk ⊕ Qk-1 (in which ⊕ means exclusive ORed), such converted data are fed to a quadrature modulator which balanced-modulates two quadrature carriers having a π/2 phase difference from each other by the data Pk and Qk. The output signal of the offset quadrature differential PSK modulator is sent to a transmission channel or memory means. And in an offset quadrature differential PSK demodulator, the signal received from the transmission channel or memory means is fed to a coherent detector, which then phase-detects the signal by two quadrature carriers having a π/2 phase difference from each other, and first and second detection outputs obtained therefrom are decoded by differential decoders and subsequently are fed to a parallel-serial converter, where the former digital data corresponding respectively to the even and odd bits are restored.
Inventors
- 👤 Nobutaka Amada
- 👤 Takaharu Noguchi
- 👤 Hiroyuki Kimura
- 👤 Masaharu Kobayashi
- 👤 Takao Arai
- 👤 Yasufumi Yumde
- 👤 Kuniaki Miura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:29
CPC Classifications
H; H03; H03D; H03D9/00; H04; H04L; H04L27/00; H04L27/18; H04L27/20; H04L27/2032; H04L27/2053; H04L27/206; H04L27/2067; H04L27/2078; H04L27/2082; G; G11; G11B; G11B20/00; G11B20/10; H04L27/22; H04L27/227
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
205 words
An offset quadrature differential phase shift keying system for modulating/demodulating digital data, comprising: first converting means for converting input digital data into a first signal Xk corresponding to even bits of said input digital data and a second signal Yk corresponding to odd bits of said input digital data, said first and second signals having a mutual deviation of one half period thereof, wherein k is an integer; first and second differential coders for differentially coding said first and second signals Xk and Yk, respectively; a quadrature modulator for balanced-modulating two quadrature carriers having a π/2 phase difference from each other by outputs of said first and second differential coders; a coherent detector for phase-detecting an output signal of said quadrature modulator, which is transmitted through a channel from said quadrature modulator, by two quadrature carriers having a T r/2 phase difference from each other; first and second differential decoders for differentially decoding outputs of said coherent detector, respectively; and second converting means for converting outputs of said first and second differential decoders into serial output digital data, odd bits of which correspond to the output of said first differential decoder and even bits of which correspond to the output of said second differential decoder.
Claim 2
Dependent Claim
205 words
An offset quadrature differential phase shift keying system for modulating/demodulating digital data, comprising: first converting means for converting input digital data into a first signal Xk corresponding to even bits of said input digital data and a second signal Yk corresponding to odd bits of said input digital data, said first and second signals having a mutual deviation of one half period thereof, wherein k is an integer; first and second differential coders for differentially coding said first and second signals Xk and Yk, respectively; a quadrature modulator for balanced-modulating two quadrature carriers having a π/2 phase difference from each other by outputs of said first and second differential coders; a coherent detector for phase-detecting an output signal of said quadrature modulator, which is transmitted through a channel from said quadrature modulator, by two quadrature carriers having a T r/2 phase difference from each other; first and second differential decoders for differentially decoding outputs of said coherent detector, respectively; and second converting means for converting outputs of said first and second differential decoders into serial output digital data, odd bits of which correspond to the output of said first differential decoder and even bits of which correspond to the output of said second differential decoder.
Claim 3
Dependent Claim
48 words
An offset quadrature differential phase shift keying system according to claim 1, wherein said first and second differential coders produce Pk and Qk as said outputs, respectively, Pk being equal to Xk⊕Pk - 1 and Qk being equal to Yk⊕Qk - 1, in which ⊕ means exclusive ORed.
Claim 4
Dependent Claim
65 words
An offset quadrature differential phase shift keying system according to claim 2, wherein each of said first and second differential coders includes an exclusive OR circuit whose one input receives the output of said first converting means, and a delay circuit which delays the output of said exclusive OR circuit and produces an output to be supplied to another input of said exclusive OR circuit.
Claim 5
Dependent Claim
142 words
An offset quadrature differential phase shift keying modulator for modulating input digital data, comprising: a serial-parallel converter for converting the input digital data into two parallel data Xk and Yk which correspond to even and odd bits of the input digital data, respectively, wherein said parallel data Xk and Yk mutually have a time difference corresponding to one half data period of said parallel data, and k is an integer; first and second differential coders for coding said data Xk and Yk into code data P k and Qk, said code data Pk being equal to Xk⊕Pk - 1 and said code data Qk being equal to Yk⊕Qk - 1, wherein ⊕ means exclusive ORed; and a quadrature modulator for balanced-modulating two quadrature carriers by said data Pk and Qk, respectively, wherein said carriers have a π/2 phase difference from each other.
Claim 6
Dependent Claim
142 words
An offset quadrature differential phase shift keying modulator for modulating input digital data, comprising: a serial-parallel converter for converting the input digital data into two parallel data Xk and Yk which correspond to even and odd bits of the input digital data, respectively, wherein said parallel data Xk and Yk mutually have a time difference corresponding to one half data period of said parallel data, and k is an integer; first and second differential coders for coding said data Xk and Yk into code data P k and Qk, said code data Pk being equal to Xk⊕Pk - 1 and said code data Qk being equal to Yk⊕Qk - 1, wherein ⊕ means exclusive ORed; and a quadrature modulator for balanced-modulating two quadrature carriers by said data Pk and Qk, respectively, wherein said carriers have a π/2 phase difference from each other.
Claim 7
Dependent Claim
194 words
An offset quadrature differential phase shift keying demodulator for demodulating an input signal, comprising: an input terminal for receiving the input signal, wherein the input signal is transmitted from an offset quadrature differential phase shift keying modulator which balanced-modulates two quadrature carriers by two parallel digital data, said two quadrature carriers having a π/2 phase difference from each other; a coherent detector for phase-detecting the input data by two quadrature carriers having a π/2 phase difference from each other; first and second code discriminators for discriminating two outputs of said coherent detector respectively so as to produce outputs Pk and Qk, wherein k is an integer; first and second differential decoders for decoding said outputs Pk and Qk into data Xk and Yk, respectively, wherein said data Xk is equal to Pk ⊕ Pk - 1 or P̅k̅⊕P̅k̅ - 1̅, said data Yk is equal to Qk⊕Qk - 1 or Q̅k̅⊕ Q̅k̅ - 1̅, and ⊕ means exclusive ORed; and a parallel-serial converter for converting said data Xk and Yk into serial output digital data, odd bits of which correspond to said data Xk and even bits of which correspond to said data Yk.
Claim 8
Dependent Claim
194 words
An offset quadrature differential phase shift keying demodulator for demodulating an input signal, comprising: an input terminal for receiving the input signal, wherein the input signal is transmitted from an offset quadrature differential phase shift keying modulator which balanced-modulates two quadrature carriers by two parallel digital data, said two quadrature carriers having a π/2 phase difference from each other; a coherent detector for phase-detecting the input data by two quadrature carriers having a π/2 phase difference from each other; first and second code discriminators for discriminating two outputs of said coherent detector respectively so as to produce outputs Pk and Qk, wherein k is an integer; first and second differential decoders for decoding said outputs Pk and Qk into data Xk and Yk, respectively, wherein said data Xk is equal to Pk ⊕ Pk - 1 or P̅k̅⊕P̅k̅ - 1̅, said data Yk is equal to Qk⊕Qk - 1 or Q̅k̅⊕ Q̅k̅ - 1̅, and ⊕ means exclusive ORed; and a parallel-serial converter for converting said data Xk and Yk into serial output digital data, odd bits of which correspond to said data Xk and even bits of which correspond to said data Yk.
Claim 9
Dependent Claim
55 words
An offset quadrature differential phase shift keying demodulator according to claim 5, wherein said first and second differential decoders include a delay circuit for delaying one of said outputs Pk and Qk and an exclusive OR circuit which exclusive-ORs said one of said outputs Pk and Qk and an output of said delay circuit, respectively.
Claim 10
Dependent Claim
137 words
An offset quadrature differential phase shift keying system for modulating digital data prior to recording said digital data on a magnetic tape by a magnetic head in a magnetic recording/reproducing apparatus, comprising: a serial-parallel converter for converting the digital data into two parallel data Xk and Yk which correspond to even and odd bits of the input digital data, respectively, wherein said parallel data Xk and Yk mutually have a time difference corresponding to one half data period of said parallel data, and k is an integer; first and second differential coders for differentially coding said parallel data Xk and Yk into code data Pk and Qk, respectively; and a quadrature modulator for balanced-modulating two quadrature carriers by said data Pk and Qk, respectively, so as to produce record data to be fed to the magnetic head.
Claim 11
Dependent Claim
137 words
An offset quadrature differential phase shift keying system for modulating digital data prior to recording said digital data on a magnetic tape by a magnetic head in a magnetic recording/reproducing apparatus, comprising: a serial-parallel converter for converting the digital data into two parallel data Xk and Yk which correspond to even and odd bits of the input digital data, respectively, wherein said parallel data Xk and Yk mutually have a time difference corresponding to one half data period of said parallel data, and k is an integer; first and second differential coders for differentially coding said parallel data Xk and Yk into code data Pk and Qk, respectively; and a quadrature modulator for balanced-modulating two quadrature carriers by said data Pk and Qk, respectively, so as to produce record data to be fed to the magnetic head.
Claim 12
Dependent Claim
38 words
An offset quadrature differential phase shift keying system according to claim 7, wherein said code data Qk is equal to Xk⊕Pk - 1, said code data Qk is equal to Yk⊕Qk - 1, and ⊕ means exclusive ORed.
Claim 13
Dependent Claim
133 words
An offset quadrature differential phase shift keying system for demodulating a signal reproduced from a magnetic tape by a magnetic head in a magnetic recording/reproducing apparatus, comprising: a coherent detector for phase-detecting the reproduced signal by two quadrature carriers having a π/2 phase difference from each other; first and second code discriminators for discriminating two outputs of said coherent detector respectively so as to produce code data Pk and Qk, wherein k is an integer; first and second differential decoders for differentially decoding said code data Pk and Qk into digital data Xk and Yk, respectively; and a parallel-serial converter for converting said digital data Xk and Yk into serial digital data, odd bits of which correspond to said digital data Xk and even bits of which correspond to said digital data Yk.
Claim 14
Dependent Claim
133 words
An offset quadrature differential phase shift keying system for demodulating a signal reproduced from a magnetic tape by a magnetic head in a magnetic recording/reproducing apparatus, comprising: a coherent detector for phase-detecting the reproduced signal by two quadrature carriers having a π/2 phase difference from each other; first and second code discriminators for discriminating two outputs of said coherent detector respectively so as to produce code data Pk and Qk, wherein k is an integer; first and second differential decoders for differentially decoding said code data Pk and Qk into digital data Xk and Yk, respectively; and a parallel-serial converter for converting said digital data Xk and Yk into serial digital data, odd bits of which correspond to said digital data Xk and even bits of which correspond to said digital data Yk.
Claim 15
Dependent Claim
275 words
an information recording/reproducing apparatus for recording/reproducing a digital audio signal on/from a magnetic medium, said digital audio signal being modulated/demodulated by a phase shift keying modulator/demodulator, comprising: a serial-parallel converter for converting the digital audio signal into two parallel audio data Xk and Yk which correspond to even and odd bits of the digital audio signal, respectively, wherein said parallel audio data Xk and Yk mutually have a time difference corresponding to one half data period, and k is an integer; first and second differential coders for coding said parallel audio data Xk and Yk into code data Pk and Qk; a quadrature modulator for balanced-modulating two quadrature carriers by said parallel audio data Pk and Qk, respectively, said two quadrature carriers having a π/2 phase difference from each other; a first magnetic recording/reproducing means for recording/reproducing an output of said quadrature modulator on/from a deep part of said magnetic medium; a coherent detector for phase-detecting said output reproduced from said deep part of said magnetic medium by two quadrature carriers having a π/2 phase difference from each other; first and second code discriminators for discriminating two outputs of said coherent detector so as to reproduce said code data Pk and Qk, respectively; first and second differential decoders for differentially decoding said reproduced code data Pk and Qk respectively so as to reproduce said parallel audio data Xk and Yk; and a parallel-serial converter for converting said reproduced parallel audio data Xk and Yk to reproduce said digital audio signal, odd bits of which correspond to said reproduced parallel audio data Xk and even bits of which correspond to said reproduced parallel audio data Yk.
Claim 16
Dependent Claim
275 words
an information recording/reproducing apparatus for recording/reproducing a digital audio signal on/from a magnetic medium, said digital audio signal being modulated/demodulated by a phase shift keying modulator/demodulator, comprising: a serial-parallel converter for converting the digital audio signal into two parallel audio data Xk and Yk which correspond to even and odd bits of the digital audio signal, respectively, wherein said parallel audio data Xk and Yk mutually have a time difference corresponding to one half data period, and k is an integer; first and second differential coders for coding said parallel audio data Xk and Yk into code data Pk and Qk; a quadrature modulator for balanced-modulating two quadrature carriers by said parallel audio data Pk and Qk, respectively, said two quadrature carriers having a π/2 phase difference from each other; a first magnetic recording/reproducing means for recording/reproducing an output of said quadrature modulator on/from a deep part of said magnetic medium; a coherent detector for phase-detecting said output reproduced from said deep part of said magnetic medium by two quadrature carriers having a π/2 phase difference from each other; first and second code discriminators for discriminating two outputs of said coherent detector so as to reproduce said code data Pk and Qk, respectively; first and second differential decoders for differentially decoding said reproduced code data Pk and Qk respectively so as to reproduce said parallel audio data Xk and Yk; and a parallel-serial converter for converting said reproduced parallel audio data Xk and Yk to reproduce said digital audio signal, odd bits of which correspond to said reproduced parallel audio data Xk and even bits of which correspond to said reproduced parallel audio data Yk.
Claim 17
Dependent Claim
29 words
ll. An information recording/reproducing apparatus according to claim 10, further comprising: a second magnetic recording/reproducing means for recording/reproducing a video signal on/from a surface part of said magnetic medium.
Claim 18
Dependent Claim
30 words
An information recording/reproducing apparatus according to claim 10, further comprising: a limiter for limiting the output of said quadrature modulator prior to supplying said output to said first recording/reproducing means.
Claim 19
Dependent Claim
30 words
An information recording/reproducing apparatus according to claim 12, further comprising: a band-pass ; filter for band-passing the output of said quadrature modulator prior to supplying said output to said limiter.
References Cited (Backward Citations)
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